Problem: Factor completely. $121c^4-44c^2+4=$
Explanation: $\begin{aligned} &\phantom{=}121 c ^4 - 44 c ^2 + 4 \\\\ &= ({11 c ^2})^2 - 2({11 c ^2})({2 })+({2 })^2 \end{aligned}$ Using the square of a difference pattern: $\begin{aligned} &\phantom{=}({11 c ^2})^2 - 2({11 c ^2})({2 })+({2 })^2 \\\\ &=({11 c ^2} - {2 })^2 \end{aligned}$ In conclusion, $121 c ^4 - 44 c ^2 + 4 =(11 c ^2 - 2 )^2$ Remember that you can always check your factorization by expanding it.